Multiple ratio electrical engraving machine



g- 11, 1959 s. w. LEVINE 2,899,493

MULTIPLE RATIO ELECTRICAL ENGRAVING MACHINE Filed Jan. 24, 1957 SAMUELWLEW/VE,

I N VEN TOR.

United States Patent MULTIPLE RATIO ELECTRICAL ENGRAVING MACHINE SamuelW. Levine, Westbury, N.Y., assignor t Fairchild Camera and InstrumentCorp., a corporation of Delaware Application January 24, 1957, SerialNo. 636,003

2 Claims. (Cl. 178--6.6)

This invention pertains to screen or half-tone engraving machines andmachines of similar type used for producing screened negatives orpositives. Machines of this type have gone into wide use, particularlyfor the production of newspaper reproductions from original photographicprints, since they eliminate the costly and time-consuming production ofphotoengravings. However, direct electrical engravers and screennegative producers are also employed for other types of graphicreproduction, both in monochrome and in multiple color work.

A good example of a successful type of photoelectrically controlledengraver is shown and described in the U.S. Reissue Letters Patent No.23,914, issued to I. A. Boyajean, In, as assignor to the owner of thepresent invention. Such machine, however, can itself produce onlyengravings which are to the same dimensional scale as the originalphotograph or other copy material which the machine is scanning. Topermit the proportions of the original to be changed in reproduction, asis often desirable in order that the engraving may fit a certain spacein the final printed matter, various expedients have been proposed.Thus, photographic enlargement of the original can be employed toproduce an intermediate print of the proper size for scanning. Machinescapable of scanning an enlarged or reduced optical image of the originalhave also been considered. All of these proposals have certaindrawbacks, either introducing additional treating steps, or requiringconsiderably more complicated apparatus than that needed for same-sizereproduction.

It is a principal object of the present invention to provide a simpleand efficient form of photoelectric engrav ing or screen negativemachine which is capable of providing, from a given original copy,engravings or screened reproductions selectively of different finalproportions or dimensions. This is to be accomplished without requiringoptical or photographic alteration of the size of the original copy, sothat the final product, such as an engraving, can be made at once aftera simple adjustment of the machine to the desired factor ofproportionality in size.

A further object of the invention is to provide a machine of the abovegeneral type in which special provision is made for preparing, at will,engravings or like half-tone screened reproductions dilfering from theoriginal copy size by certain standard or predetermined size factors, sothat for a given standard size of original copy, the machine can be setvery rapidly and accurately to provide a finished screened product ofany selected one of a range of sizes. Thus, for example, the machine maybe designed to derive directly from a standard 4 by 5 inch originalphotograph a final engraving plate whose size is suitable for one, twoor three-column display, or other unit size, as in a newspaper or thelike. The satisfactory achievement of this object of the inventionpermits great simplification of operations, and considerable savings intime, labor and material in printing operations.

Still another object of the invention is to provide a machine of thecylindrical scanner type in which the desired proportional change inengraving size in one direction (length or width) is accomplished by asimple lever system, while the corresponding change in size in the otherdirection (width or length) is obtained by selection of a cylinder ofproper diameter, from among several interchangeable cylinders ofdifferent diameters. This separation of the control of the sizeproportionality factor between the two directions incidentally permitsnon-proportional changes in size, including the possibility of enlargingor reducing only one dimension of the original material. Suchpossibility permits the accomplishment of various useful ends, includingselective distortion, and the accomplishment of slight size changes inone dimension only to make the engraving fit a special purpose. In thelatter case, the size change would be accomplished by adjusting thelever system only, and utilizing scanning and engraving cylinders of thesame diameter, so that the continuous ratio adjustment inherent in thelever system is utilized. For the reproduction of odd or non-standardsizes of originals, the machine may be set to produce that selected sizechange resulting in the next larger standard size of finished engraving,and the final engraving plate or similar sheet trimmed or cropped in oneor both dimensions to satisfy the dimensional requirements involved.This is not a drawback in the general case, because most pictorialmatter can readily be edge trimmed to a degree without loss of value,and indeed such trimming is commonplace in the graphic arts field.

While the above objects have been stated mainly in connection with themaking of direct engravings on a plastic or metal sheet, the system isalso advantageous where the sheet is a photosensitive material, such asphotographic film or paper. In this case, the engraving head is replacedby a transducer which converts the signals obtained from the copy to ashaped optical beam producing exposure dots of variable size on thesheet, the sheet being later processed photographically to produce thedesired screen pattern. Moreover, when used with this type oftransducer, the sheet may consist of a suitable light-hardenable plasticor photopolymer, the dot exposure providing point-topoint selectivepolymerization. Such a sheet or plate, when developed as by subsequentwashing or etching, can be used directly for printing purposes, or forduplication by known stereotype or matting processes.

The above and other objects and advantages of the invention will best beunderstood by referring now to the following detailed specification of apreferred embodiment of the invention, taken in connection with theappended drawings, in which:

Fig. 1 is a front elevation of a machine embodying the principles of theinvention, with certain parts indicated diagrammatically.

Fig. 2 is a fragmentary sectional view, to a larger scale, of a portionof the machine, the section plane being indicated by the dash line andarrows 2-2 of Fig. 1.

Fig. 3 is a similar sectional view, taken on line 33 of Fig. l, butillustrating the manner in which any of several interchangeable copycylinders may be employed to effect a size change in one direction.

In the description which follows, a particular form of the invention,presently preferred, is treated in considerable detail, in order thatthose skilled in the art may apprehend the novel principles of theinvention, and so that they may readily practice the same. However, itwill be understood that these details are not intended as limiting thescope of the invention itself, which scope is indicated by the claimsfollowing the present description. Also, certain of the details of themachine which are well known of and in themselves, are indicated merelyschematically, to avoid encumbering the description and drawingsunnecessarily As has been stated, the present embodiment of theinvention is of the cylinder type; that is, the original photo or copyis wrapped about a scanner cylinder, and the plastic, metal or similarsheet to be engraved is wrapped about a second cylinder, hereinaftercalled the engraver cylinder. In the Boyajean patent mentioned earlier,these cylinders are coaxial, one beside the other, and a flexible drivetape (driven in timed relation to the rotation of the two cylinders)operates to traverse a pair of carriages in a linear path along therespective surfaces of the two cylinders. One carriage carries aphotoelectric system which scans each point of the original copy in ahelical scanning pattern, and the other carriage supports a stylus motordriving an engraving stylus into the plastic or like engraveable sheet,to depths determined by the signal derived from the scanner device.

In the present invention, the two cylinders, While generally of the typedescribed by Boyajean, are not coaxial, but are arranged one verticallyabove the other with their drive shafts parallel and connected bygearing for simultaneous and synchronous rotation. Supports such asguide strips or ways are provided for the carriages, one of which isagain driven by a flexible tape as described above. However, the othercarriage is driven by the motion of the first carriage through anadjustable lever, whose effective center of rotation can be moved to lieat different distances from the points at which the lever is connectedto the carriages. Thus, by varying the relative lever arms, any desiredproportionality factor between the carriage traverse motions can beobtained, and this effects the desired relative size change in onedirection. The size change in the other direction on the sheet isobtained by providing several different copy-carrying or scanningcylinders, so that the unity gearing between the cylinder shaftsactually results in an effective change in the peripheral velocity ofone cylinder relative to the other.

With the above explanation in mind, the drawings will readily beunderstood. In Fig. 1, reference numeral designates a suitable baseplate or support for the entire apparatus, and it is provided with apair of upright columns 12 and 14, shown as I-beams, and forming themain framework of the device. Near the upper ends of these I-beams, atransverse bar 16 extends horizontally between them, forming at once aframe element and also a horizontal guideway for the scanner carriage 18which is slidable therealong. At an intermediate height, a secondhorizontal bar 20 connects the vertical beams or columns, also servingas a frame element and as a guideway for the engraver carriage 22.

A main drive motor 24 is belted to a pulley-flywheel 26 whose shaft 30carries a tone wheel 28 for dot signal modulation in a manner describedin the Boyajean patent; for simplicity, the tone wheel 28 is shown as anoptical wheel cooperating with a light source and photocell to producethe desired pulses in timed relation to the rotation of shaft 30. Thelatter is connected by a manually operable clutch 32 to a cross-shaft 34journalled in the uprights 12 and 14. While the shaft is shown as onepiece, it may effectively be two pieces terminating in couplings such a36 so that the engraver cylinder 38 can be changed if desired. Rotationof shaft 34 thus rotates the engraver cylinder at a speed determined bymotor 24.

At the right end of cylinder 38, shaft 34 or its equivalent extendsthrough a suitable bearing in upright 14 and is secured to a bevel gear40. The extreme right end of the shaft 34 may be journalled in anauxiliary upright 42, which also serves to support bearing bracketscarrying a shaft provided with bevel gears 44 and 46, which transmit therotation to the upper cross shaft section 48 by a final bevel gear 58secured thereon. The opposite section of the cross shaft is designated52, and both sections terminate, at their inner ends, at couplings 54which permit the scanner cylinder 56 to be removed and replaced quicklyand without dis-assembling the apparatus.

Returning now to the engraver carriage 22, means are provided forcausing the same to traverse slowly along its guide bar 20. Such meansmay include a flexible but inextensible tape 58, preferably metal,carried tautly upon wheels 60, 62 supported by the uprights 12 and 14,one wheel such as 60 being driven by a suitable pulley and a belt 64from a speed-reducing transmission, not shown, but which may form a partof the clutch device 32. Carriage 22 is releasably locked to one pass oftape 58, as by a clamp 66 as in the case of the Boyajean machine.Carriage 22 supports a stylus motor 68 and stylus also as described inthe prior patent, for cooperation with the engravable sheet Wrappedabout cylinder 38.

In this way, the carriage may be moved rapidly to the desired startingpoint, and then clamped to tape or belt 58 for regular traverse so thatthe stylus will trace the desired helical motion path on the cylinder.Preferably, the stylus motor 68 is carried in vertical ways on carriage22, to maintain proper stylus pressure on the sheet being engraved.Suitable limit switches are of course provided, in well known way, toprevent any possibility of driving the carriage 22 into contact with thesupports 12 and 14 or other parts. After completion of one pass, thecarriage may be returned manually to the starting position (at eitherend according to the design of the machine), either by de-clutching thedrive at 32 or at clamp 66.

In order to drive the other carriage 18 distances proportional to thosetraversed by carriage 22, the former is driven along its guide 16directly from the engraver carriage, and by a variable-ratio linkagewhose major component is the lever bar 70. This lever is pivoted (forexample, at its center) for free swinging movements on a verticallymovable carriage 72. Numeral 74 designates the pivot bolt for thislever. The carriage 72 may, for instance, be slidable on ways 76, 78also extending upwardly from base 10 and suitably braced. Screws such as80 permit the carriage 72 to be locked firmly in its adjusted position,which position determines the effective lever ratio between the arms ofthe linkage. A ratio scale 82 may be provided to enable theproportionality factor to be set as desired. Where pre-determined ratiosare contemplated, suitable detent means may be provided for rapidsetting.

At either end of lever 70, it is slotted as at 84, 86, and in each slotis received a corresponding bearing sleeve extending rearwardly from therespective carriage 18 and 22. One such sleeve is better shown in Fig.2, which shows the parts associated with carriage 22 to a larger scale.The pin-and-slot connections ensure strictly proportional motions of thetwo carriages, and if the lever arm pivot is exactly in the center ofthe distance between the carriage pins or sleeves, the ratio will beunity. By adjusting carriage 72, deviations in either direction(enlargement or reduction) are readily obtained. This will accomplishthe desired change in scale in one direction of the copy and engraving;to wit, the direction parallel to the cylinder axes.

To allow for scale changes in the other direction with respect to theoriginal copy and the engraving, provision is made for substitutingeither for the cylinder 38 or the cylinder 56 a cylinder of differentdiameter. In the form shown, and most conveniently, the cylinder 56 isreplaced, and as stated above, provision is made so that thesubstitution can be made without dis-assembly. The couplings 54 permitthis to be done. Fig. 3 details one possible arrangement, a coupling 54being shown as a flange 84 at one free end of one section of shaft 48.The flange has an approximately semi-circular recess 86 into which astub shaft at the end of the cylinder may be dropped, and locked inplace as by a pivoted catch 88, and the stub shaft may be keyed to theflange, as indicated in Fig. 3, for positive drive. A cylinder of largersize than cylinder 56 is illustrated in dash lines at 88.

The photoelectric scanner assembly on carriage 18 is preferably mountedthereon by means of a double-action support 90 which permits it to beadjusted both vertically (toward and away from the cylinder 56) andhorizontally. The former motion is desirable to permit accurate focusingof the scanner system on the periphery of the cylinder, where adifferent size is substituted, and the horizontal motion permits properphasing of horizontal position of the scanner to allow for slightmisplacement of the copy on that cylinder. This permits the first lineof the engraving to represent accurately one margin of the area of theoriginal desired to be reproduced.

As was stated earlier, the sheet carried by cylinder 38 may be aphotosensitive material such as photographic paper or film, or even alight-hardenable photopolymer or the like. In this case, the engravinghead or stylus motor 68 will be replaced by a suitable optical beamoutput transducer controlled in the same manner by the signals from thescanning head on carriage 19. Such an optical output transducer is shownand described in the copending application of the same inventor, SerialNo. 455,177, filed September 10, 1954, and owned by the assignee of thepresent invention.

In view of the above, it will be realized that the novel aspects of theinvention do not depend upon the use of any particular output device,whether an engraver or exposing transducer, nor indeed upon whether thefinal sheet is an engraving or merely a screened negative or positiveplanographic reproduction or photograph. Hence no limitation is to beimplied by the fact that this description has been directed to certainspecific kinds of processes and products, and to the appropriatecorresponding output devices.

A very useful application of this machine is in the newspaper field inconjunction with a camera of the highspeed self developing type such asthe Land Polaroid camera and film. Since the size of the film or printfrom the camera would always be standard, and the column widths in thenewspaper would also be multiples of a single column width, exact sizesof cylinders could be furnished for enlarging or reducing such aphotograph to any desired multiple of the newspaper column width. Theadvantage of such an application would be the complete elimination ofthe photographic laboratory in the process of getting a picture ofinterest into a printing plate. The picture taken by the photographerwould be removed from the camera as a reflection copy, placed on theappropriate size cylinder 56, and the engraving or other screenedreproduction made very quickly after the original copy had been exposed.

For the purposes of the present description, the signal channelsconnecting the scanning head, the tone wheel output, and the engravingor exposing output device have been omitted for clarity. Such channelsand the necessary amplifiers are well shown in the Boyajean patent, andthe disclosure therein of such parts is to be considered as includedherein for purposes of reference.

What is claimed is:

1. A photoelectric machine for making screened plates directly fromoriginal copy and to altered dimensional proportions, comprising a pairof cylinders adapted respectively to receive the original copy and animage receiving plate in wrap-around fashion, means for rotating saidcylinders in synchronism, respective carriages mounted to traverse pathsadjacent the cylinders and parallel to the cylinder axes, scanning meanscarried by one carriage for scanning copy on one cylinder,patternreproducing means carried by the other carriage for operatingupon a plate on the other cylinder, power means for driving one of saidcarriages at a rate proportional to the rotational speed of thecylinders, and a variableratio linkage connecting the other carriage formovement thereof from the first carriage, said linkage comprising asingle bar having a pin-and-slot connection with both carriages, andmeans for adjusting the position of the pivot axis of said lever withrespect to the carriages.

2. The combination of claim 1, in which said cylinders are disposed inspaced parallel relationship, and in which the linkage comprises a leverpivoted upon a pivot support adjustable with respect to its distancefrom the respective carriages.

References Cited in the file of this patent UNITED STATES PATENTS1,923,208 Howey Aug. 22, 1933 2,251,828 Hammond Aug. 5, 1941 2,520,761Giel Aug. 29, 1950 2,606,245 Hall Aug. 5, 1952

